Gardenia thunbergia

Wild gardenia

Gardenia thunbergia ‘wild gardenia’, ‘witkatjiepiering’

The genus Gardenia is a member of the coffee family Rubiaceae. It is native to the subtropical and tropical parts of Africa, southern Asia, Australia, and the islands of the tropical Pacific Ocean. There are more than 140 species worldwide, but just five occur in South Africa. The gardenia commonly grown in gardens in South Africa is the sweet-scented G. jasminoides from southern Asia. G. thunbergia, the wild gardenia, is just as showy, and is more heavily sweet-scented, especially at night. In addition, its waxy-white flowers have distinctive slender perianth tubes up to 120 mm long. It occurs naturally in evergreen forest along a narrow coastal strip from Grahamstown in the Eastern Cape to Kosi Bay in northern KwaZulu-Natal, and north into tropical Africa. It forms a dense, spreading shrub or small tree 2-5 m high, and its blooming period is throughout summer – with a peak in January and February. The flowers have 7-8 spreading petals and the prominent egg-shaped fruits are hard and remain on the branches for many months, or even years. The glossy leaves are borne in clusters near the branch tips, and have prominent depressed veins on the upper surface. This very long-lived, slow-growing plant has a beautiful smooth, whitish-grey trunk and branches.

Gardenia thunbergia is an excellent subject for small, medium-sized or large gardens – its sweet perfume wafting through the air for quite a distance. It can take full sun, but prefers a partially-shaded position in a well-drained, acidic soil containing plenty of well-decomposed organic matter. It is resistant to light frost and is fairly drought tolerant in winter, but prefers plenty of moisture throughout the year, especially in summer, and benefits from heavy mulching. It can be used as a specimen subject in the informal border or near ponds, and can also be grown in large containers in a lightly-shaded courtyard or beside garden steps. The roots of G. thunbergia are not invasive, and plants can be placed close to garden walls and within brick paving.

Propagation is from seeds sown from late spring to mid-summer, which germinate within a month to 6 weeks. To access the seeds, the extremely hard fruits have to be broken open with a heavy-duty hammer, and scooped out with a spoon.

Alternatively, large cuttings 100-120 mm long, from new growth, can be taken at any time in summer, and rooted under mist.

The Gardener